small example showing testing and code coverage with Maven / JUnit / …

…JaCoCo

.gitignore

@@ -0,0 +1,9 @@
+# Mac stuff
+.DS_Store
+
+# Emacs temp files
+*~
+\#*\#
+
+# Maven build stuff
+target/

README.md

@@ -0,0 +1,10 @@
+# Basic Testing Setup for Java #
+
+This code uses [`maven`](https://maven.apache.org/) as a Java build tool.
+Maven is responsible for managing dependencies and automating running the code.
+
+- To compile all code: `mvn compile`
+- To run all tests: `mvn test`
+- To determine coverage information:
+    - `mvn jacoco:report`
+    - Open `target/site/jacoco/index.html` for an HTML coverage report

pom.xml

@@ -0,0 +1,46 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>trees</groupId>
+  <artifactId>trees</artifactId>
+  <packaging>jar</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <name>maven_testing_example</name>
+  <url>http://maven.apache.org</url>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.13</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.jacoco</groupId>
+        <artifactId>jacoco-maven-plugin</artifactId>
+        <version>0.8.7</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>prepare-agent</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>report</id>
+            <phase>prepare-package</phase>
+            <goals>
+              <goal>report</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <properties>
+    <java.version>1.8</java.version>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+</project>

src/main/java/maven_testing_example/Example.java

@@ -0,0 +1,21 @@
+package maven_testing_example;
+
+public class Example {
+    public static int doOperation(final int opCode,
+                                  final int operand1,
+                                  final int operand2) throws InvalidOpCodeException {
+        if (opCode == 0) {
+            // addition
+            return operand1 + operand2;
+        } else if (opCode == 1) {
+            return operand1 - operand2;
+        } else if (opCode == 2) {
+            return operand1 * operand2;
+        } else if (opCode == 3) {
+            return operand1 / operand2;
+        } else {
+            throw new InvalidOpCodeException(opCode);
+        }
+    } // doOperation
+} // Example
+

src/main/java/maven_testing_example/InvalidOpCodeException.java

@@ -0,0 +1,13 @@
+package maven_testing_example;
+
+public class InvalidOpCodeException extends Exception {
+    // ---BEGIN INSTANCE VARIABLES---
+    public final int opCode;
+    // ---END INSTANCE VARIABLES---
+
+    public InvalidOpCodeException(final int opCode) {
+        super("Invalid op code: " + opCode);
+        this.opCode = opCode;
+    }
+} // InvalidOpCodeException
+

src/test/java/maven_testing_example/ExampleTest.java

@@ -0,0 +1,31 @@
+package maven_testing_example;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class ExampleTest {
+    @Test
+    public void testOpCode0() throws InvalidOpCodeException {
+        assertEquals(3, Example.doOperation(0, 1, 2));
+    }
+
+    @Test
+    public void testOpCode1() throws InvalidOpCodeException {
+        assertEquals(5, Example.doOperation(1, 8, 3));
+    }
+
+    @Test
+    public void testOpCode2() throws InvalidOpCodeException {
+        assertEquals(20, Example.doOperation(2, 5, 4));
+    }
+
+    @Test
+    public void testOpCode3() throws InvalidOpCodeException {
+        assertEquals(3, Example.doOperation(3, 15, 5));
+    }
+
+    @Test(expected = InvalidOpCodeException.class)
+    public void testInvalidOpCode() throws InvalidOpCodeException {
+        Example.doOperation(4, 0, 0);
+    }
+} // ExampleTest